1. Field of the Invention
This invention relates to an electronic photographing device, or more particularly, to an electronic photographing device wherein the tonal characteristic of electrostatic latent image formed on the light sensitive body is improved to obtain a fogless reproduced image.
2. Description of the Prior Art
The images formed by conventional electrophotography are difficult to conform to the originals and reproduction of original gradation is difficult due to the tone hardness of the electrostatic latent image characteristic of the light sensitive body which is mainly expressed by Do (original density) - Vs (surface potential of light sensitive body) characteristic.
Although the improvement of gradation is important in monochromatic reproduced images, it is very important in multi-color imaging for color reproduction and for keeping color balance.
The method described in Ser. No. 929,508 (June 27, 1978) proposed before this applicant is very effective because the method made it possible to reproduce original gradation faithfully by expanding the original density reproducible range of the Do-Vs characteristic.
However, if the configuration and condition of the original optical image exposure to a simultaneous de-electrifying means were inappropriate there were cases where multiples of electric power of the original illuminating lamp was required, compared with the case of ordinary optical image exposure to simultaneous de-electrification in which no control is made on the gradation. Moreover, the effect of gradation control was not sufficient.
Particularly in a color copying device, the above-mentioned increase in the power of the illuminating lamp is an important problem in performing color separation exposure, and in some cases where halogen lamps were used, yellow fogging was produced due to the shortage in the amount of light of blue component.
This invention was made to solve the above-mentioned problems.